body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
}

#app {
    text-align: center;
}

header {
    background-color: #333;
    color: white;
    padding: 1em 0;
}

nav {
    display: flex;
    justify-content: center;
    gap: 1em;
}

nav button {
    padding: 0.5em 1em;
    border: none;
    background-color: #444;
    color: white;
    cursor: pointer;
}

nav button.active {
    background-color: #007bff;
}

main {
    padding: 1em;
}
